Psychiatric problems sharply increase after cross-sex hormones in adolescents.

In a Finnish nationwide study of 2,083 gender-referred youth, the proportion needing specialist psychiatric treatment rose markedly after starting cross-sex hormones: from 9.8% to 60.7% in males and from 21.6% to 54.5% in females. After adjustment for prior psychiatric history, the risk remained 3–6 times higher than in matched population controls.

Ruuska, S.-M., Tuisku, K., Holttinen, T., and Kaltiala, R. (2026). “Psychiatric Morbidity Among Adolescents and Young Adults Who Contacted Specialised Gender Identity Services in Finland in 1996–2019: A Register Study,” Acta Paediatrica: 1–9. https://doi.org/10.1111/apa.70533.